What is a Diode?
An LED is a light emitting diode. A semiconductor diode is a two-terminal device, sometimes described as a pn. An LED is fabricated from a semiconductor material. One side of the semiconductor is attached to the P side which is the anode; the other side of the semiconductor is attached to the N side, the cathode. Electricity can flow from the p side to the n side. However, no electricity can flow in reverse. In effect, therefore, a diode is a unidirectional conductor.
In simple language, a diode is like a valve, a one-way valve, which allows electric current to flow in one direction but generally does not allow it to flow in the opposite direction. The direction of the electric current in the diode may be reversed. However, even if it is, the flow will still be one directional. A diode contains two electrodes that act in much the same manner as semiconductors. The positive or p-type is usually the anode and the negative or n-type is the cathode. In other words, the cathode is negatively charged as compared to the anode. If the cathode is charged at the same or very similar voltage to the anode, current will not flow. In electronics, a diode acts similarly to charge carriers. Diodes can also be compared to check valves or switches. If liquid or water were involved instead of current, it would essentially be similar to water flowing upstream or downstream. Put simply, a diode tends to allow for upstream to downstream flow but not the other way around.
A diode is simply the main building block of semiconductors. It’s a great little device that limits current flow to one direction. There are 2 sides to a diode; the anode (the positive side) and the cathode (the negative side). To turn on a diode, or to “forward bias” it, the anode must be “more positive” than the cathode. To turn off a diode, or to “reverse bias” it, the anode must be “less positive” than the cathode.
The diode element consists of a structure called the pn junction. The terminal attached to the p-type semiconductor is called the anode, and the terminal attached to the n-type semiconductor is called the cathode. Current is allowed to flow from the anode to the cathode, but almost completely prevented from flowing in the reverse direction. This phenomenon is called rectification, and, put simply, it converts alternating current to a unidirectional current.
